diff options
Diffstat (limited to 'compiler/rustc_abi/src/lib.rs')
| -rw-r--r-- | compiler/rustc_abi/src/lib.rs | 295 |
1 files changed, 259 insertions, 36 deletions
diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs index a438545c76f..de4b5a46c81 100644 --- a/compiler/rustc_abi/src/lib.rs +++ b/compiler/rustc_abi/src/lib.rs @@ -221,6 +221,20 @@ impl ReprOptions { /// * Cranelift stores the base-2 log of the lane count in a 4 bit integer. pub const MAX_SIMD_LANES: u64 = 1 << 0xF; +/// How pointers are represented in a given address space +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +pub struct PointerSpec { + /// The size of the bitwise representation of the pointer. + pointer_size: Size, + /// The alignment of pointers for this address space + pointer_align: AbiAlign, + /// The size of the value a pointer can be offset by in this address space. + pointer_offset: Size, + /// Pointers into this address space contain extra metadata + /// FIXME(workingjubilee): Consider adequately reflecting this in the compiler? + _is_fat: bool, +} + /// Parsed [Data layout](https://llvm.org/docs/LangRef.html#data-layout) /// for a target, which contains everything needed to compute layouts. #[derive(Debug, PartialEq, Eq)] @@ -236,13 +250,22 @@ pub struct TargetDataLayout { pub f32_align: AbiAlign, pub f64_align: AbiAlign, pub f128_align: AbiAlign, - pub pointer_size: Size, - pub pointer_align: AbiAlign, pub aggregate_align: AbiAlign, /// Alignments for vector types. pub vector_align: Vec<(Size, AbiAlign)>, + pub default_address_space: AddressSpace, + pub default_address_space_pointer_spec: PointerSpec, + + /// Address space information of all known address spaces. + /// + /// # Note + /// + /// This vector does not contain the [`PointerSpec`] relative to the default address space, + /// which instead lives in [`Self::default_address_space_pointer_spec`]. + address_space_info: Vec<(AddressSpace, PointerSpec)>, + pub instruction_address_space: AddressSpace, /// Minimum size of #[repr(C)] enums (default c_int::BITS, usually 32) @@ -267,14 +290,20 @@ impl Default for TargetDataLayout { f32_align: AbiAlign::new(align(32)), f64_align: AbiAlign::new(align(64)), f128_align: AbiAlign::new(align(128)), - pointer_size: Size::from_bits(64), - pointer_align: AbiAlign::new(align(64)), aggregate_align: AbiAlign { abi: align(8) }, vector_align: vec![ (Size::from_bits(64), AbiAlign::new(align(64))), (Size::from_bits(128), AbiAlign::new(align(128))), ], - instruction_address_space: AddressSpace::DATA, + default_address_space: AddressSpace::ZERO, + default_address_space_pointer_spec: PointerSpec { + pointer_size: Size::from_bits(64), + pointer_align: AbiAlign::new(align(64)), + pointer_offset: Size::from_bits(64), + _is_fat: false, + }, + address_space_info: vec![], + instruction_address_space: AddressSpace::ZERO, c_enum_min_size: Integer::I32, } } @@ -288,6 +317,7 @@ pub enum TargetDataLayoutErrors<'a> { InconsistentTargetArchitecture { dl: &'a str, target: &'a str }, InconsistentTargetPointerWidth { pointer_size: u64, target: u32 }, InvalidBitsSize { err: String }, + UnknownPointerSpecification { err: String }, } impl TargetDataLayout { @@ -298,6 +328,7 @@ impl TargetDataLayout { /// determined from llvm string. pub fn parse_from_llvm_datalayout_string<'a>( input: &'a str, + default_address_space: AddressSpace, ) -> Result<TargetDataLayout, TargetDataLayoutErrors<'a>> { // Parse an address space index from a string. let parse_address_space = |s: &'a str, cause: &'a str| { @@ -321,19 +352,27 @@ impl TargetDataLayout { |s: &'a str, cause: &'a str| parse_bits(s, "size", cause).map(Size::from_bits); // Parse an alignment string. - let parse_align = |s: &[&'a str], cause: &'a str| { - if s.is_empty() { - return Err(TargetDataLayoutErrors::MissingAlignment { cause }); - } + let parse_align_str = |s: &'a str, cause: &'a str| { let align_from_bits = |bits| { Align::from_bits(bits) .map_err(|err| TargetDataLayoutErrors::InvalidAlignment { cause, err }) }; - let abi = parse_bits(s[0], "alignment", cause)?; + let abi = parse_bits(s, "alignment", cause)?; Ok(AbiAlign::new(align_from_bits(abi)?)) }; + // Parse an alignment sequence, possibly in the form `<align>[:<preferred_alignment>]`, + // ignoring the secondary alignment specifications. + let parse_align_seq = |s: &[&'a str], cause: &'a str| { + if s.is_empty() { + return Err(TargetDataLayoutErrors::MissingAlignment { cause }); + } + parse_align_str(s[0], cause) + }; + let mut dl = TargetDataLayout::default(); + dl.default_address_space = default_address_space; + let mut i128_align_src = 64; for spec in input.split('-') { let spec_parts = spec.split(':').collect::<Vec<_>>(); @@ -344,24 +383,107 @@ impl TargetDataLayout { [p] if p.starts_with('P') => { dl.instruction_address_space = parse_address_space(&p[1..], "P")? } - ["a", a @ ..] => dl.aggregate_align = parse_align(a, "a")?, - ["f16", a @ ..] => dl.f16_align = parse_align(a, "f16")?, - ["f32", a @ ..] => dl.f32_align = parse_align(a, "f32")?, - ["f64", a @ ..] => dl.f64_align = parse_align(a, "f64")?, - ["f128", a @ ..] => dl.f128_align = parse_align(a, "f128")?, - // FIXME(erikdesjardins): we should be parsing nonzero address spaces - // this will require replacing TargetDataLayout::{pointer_size,pointer_align} - // with e.g. `fn pointer_size_in(AddressSpace)` - [p @ "p", s, a @ ..] | [p @ "p0", s, a @ ..] => { - dl.pointer_size = parse_size(s, p)?; - dl.pointer_align = parse_align(a, p)?; + ["a", a @ ..] => dl.aggregate_align = parse_align_seq(a, "a")?, + ["f16", a @ ..] => dl.f16_align = parse_align_seq(a, "f16")?, + ["f32", a @ ..] => dl.f32_align = parse_align_seq(a, "f32")?, + ["f64", a @ ..] => dl.f64_align = parse_align_seq(a, "f64")?, + ["f128", a @ ..] => dl.f128_align = parse_align_seq(a, "f128")?, + [p, s, a @ ..] if p.starts_with("p") => { + let mut p = p.strip_prefix('p').unwrap(); + let mut _is_fat = false; + + // Some targets, such as CHERI, use the 'f' suffix in the p- spec to signal that + // they use 'fat' pointers. The resulting prefix may look like `pf<addr_space>`. + + if p.starts_with('f') { + p = p.strip_prefix('f').unwrap(); + _is_fat = true; + } + + // However, we currently don't take into account further specifications: + // an error is emitted instead. + if p.starts_with(char::is_alphabetic) { + return Err(TargetDataLayoutErrors::UnknownPointerSpecification { + err: p.to_string(), + }); + } + + let addr_space = if !p.is_empty() { + parse_address_space(p, "p-")? + } else { + AddressSpace::ZERO + }; + + let pointer_size = parse_size(s, "p-")?; + let pointer_align = parse_align_seq(a, "p-")?; + let info = PointerSpec { + pointer_offset: pointer_size, + pointer_size, + pointer_align, + _is_fat, + }; + if addr_space == default_address_space { + dl.default_address_space_pointer_spec = info; + } else { + match dl.address_space_info.iter_mut().find(|(a, _)| *a == addr_space) { + Some(e) => e.1 = info, + None => { + dl.address_space_info.push((addr_space, info)); + } + } + } + } + [p, s, a, _pr, i] if p.starts_with("p") => { + let mut p = p.strip_prefix('p').unwrap(); + let mut _is_fat = false; + + // Some targets, such as CHERI, use the 'f' suffix in the p- spec to signal that + // they use 'fat' pointers. The resulting prefix may look like `pf<addr_space>`. + + if p.starts_with('f') { + p = p.strip_prefix('f').unwrap(); + _is_fat = true; + } + + // However, we currently don't take into account further specifications: + // an error is emitted instead. + if p.starts_with(char::is_alphabetic) { + return Err(TargetDataLayoutErrors::UnknownPointerSpecification { + err: p.to_string(), + }); + } + + let addr_space = if !p.is_empty() { + parse_address_space(p, "p")? + } else { + AddressSpace::ZERO + }; + + let info = PointerSpec { + pointer_size: parse_size(s, "p-")?, + pointer_align: parse_align_str(a, "p-")?, + pointer_offset: parse_size(i, "p-")?, + _is_fat, + }; + + if addr_space == default_address_space { + dl.default_address_space_pointer_spec = info; + } else { + match dl.address_space_info.iter_mut().find(|(a, _)| *a == addr_space) { + Some(e) => e.1 = info, + None => { + dl.address_space_info.push((addr_space, info)); + } + } + } } + [s, a @ ..] if s.starts_with('i') => { let Ok(bits) = s[1..].parse::<u64>() else { parse_size(&s[1..], "i")?; // For the user error. continue; }; - let a = parse_align(a, s)?; + let a = parse_align_seq(a, s)?; match bits { 1 => dl.i1_align = a, 8 => dl.i8_align = a, @@ -379,7 +501,7 @@ impl TargetDataLayout { } [s, a @ ..] if s.starts_with('v') => { let v_size = parse_size(&s[1..], "v")?; - let a = parse_align(a, s)?; + let a = parse_align_seq(a, s)?; if let Some(v) = dl.vector_align.iter_mut().find(|v| v.0 == v_size) { v.1 = a; continue; @@ -390,10 +512,27 @@ impl TargetDataLayout { _ => {} // Ignore everything else. } } + + // Inherit, if not given, address space information for specific LLVM elements from the + // default data address space. + if (dl.instruction_address_space != dl.default_address_space) + && dl + .address_space_info + .iter() + .find(|(a, _)| *a == dl.instruction_address_space) + .is_none() + { + dl.address_space_info.push(( + dl.instruction_address_space, + dl.default_address_space_pointer_spec.clone(), + )); + } + Ok(dl) } - /// Returns **exclusive** upper bound on object size in bytes. + /// Returns **exclusive** upper bound on object size in bytes, in the default data address + /// space. /// /// The theoretical maximum object size is defined as the maximum positive `isize` value. /// This ensures that the `offset` semantics remain well-defined by allowing it to correctly @@ -404,7 +543,26 @@ impl TargetDataLayout { /// so we adopt such a more-constrained size bound due to its technical limitations. #[inline] pub fn obj_size_bound(&self) -> u64 { - match self.pointer_size.bits() { + match self.pointer_size().bits() { + 16 => 1 << 15, + 32 => 1 << 31, + 64 => 1 << 61, + bits => panic!("obj_size_bound: unknown pointer bit size {bits}"), + } + } + + /// Returns **exclusive** upper bound on object size in bytes. + /// + /// The theoretical maximum object size is defined as the maximum positive `isize` value. + /// This ensures that the `offset` semantics remain well-defined by allowing it to correctly + /// index every address within an object along with one byte past the end, along with allowing + /// `isize` to store the difference between any two pointers into an object. + /// + /// LLVM uses a 64-bit integer to represent object size in *bits*, but we care only for bytes, + /// so we adopt such a more-constrained size bound due to its technical limitations. + #[inline] + pub fn obj_size_bound_in(&self, address_space: AddressSpace) -> u64 { + match self.pointer_size_in(address_space).bits() { 16 => 1 << 15, 32 => 1 << 31, 64 => 1 << 61, @@ -415,7 +573,18 @@ impl TargetDataLayout { #[inline] pub fn ptr_sized_integer(&self) -> Integer { use Integer::*; - match self.pointer_size.bits() { + match self.pointer_offset().bits() { + 16 => I16, + 32 => I32, + 64 => I64, + bits => panic!("ptr_sized_integer: unknown pointer bit size {bits}"), + } + } + + #[inline] + pub fn ptr_sized_integer_in(&self, address_space: AddressSpace) -> Integer { + use Integer::*; + match self.pointer_offset_in(address_space).bits() { 16 => I16, 32 => I32, 64 => I64, @@ -439,6 +608,66 @@ impl TargetDataLayout { Align::from_bytes(vec_size.bytes().next_power_of_two()).unwrap(), )) } + + /// Get the pointer size in the default data address space. + #[inline] + pub fn pointer_size(&self) -> Size { + self.default_address_space_pointer_spec.pointer_size + } + + /// Get the pointer size in a specific address space. + #[inline] + pub fn pointer_size_in(&self, c: AddressSpace) -> Size { + if c == self.default_address_space { + return self.default_address_space_pointer_spec.pointer_size; + } + + if let Some(e) = self.address_space_info.iter().find(|(a, _)| a == &c) { + e.1.pointer_size + } else { + panic!("Use of unknown address space {c:?}"); + } + } + + /// Get the pointer index in the default data address space. + #[inline] + pub fn pointer_offset(&self) -> Size { + self.default_address_space_pointer_spec.pointer_offset + } + + /// Get the pointer index in a specific address space. + #[inline] + pub fn pointer_offset_in(&self, c: AddressSpace) -> Size { + if c == self.default_address_space { + return self.default_address_space_pointer_spec.pointer_offset; + } + + if let Some(e) = self.address_space_info.iter().find(|(a, _)| a == &c) { + e.1.pointer_offset + } else { + panic!("Use of unknown address space {c:?}"); + } + } + + /// Get the pointer alignment in the default data address space. + #[inline] + pub fn pointer_align(&self) -> AbiAlign { + self.default_address_space_pointer_spec.pointer_align + } + + /// Get the pointer alignment in a specific address space. + #[inline] + pub fn pointer_align_in(&self, c: AddressSpace) -> AbiAlign { + if c == self.default_address_space { + return self.default_address_space_pointer_spec.pointer_align; + } + + if let Some(e) = self.address_space_info.iter().find(|(a, _)| a == &c) { + e.1.pointer_align + } else { + panic!("Use of unknown address space {c:?}"); + } + } } pub trait HasDataLayout { @@ -1100,10 +1329,7 @@ impl Primitive { match self { Int(i, _) => i.size(), Float(f) => f.size(), - // FIXME(erikdesjardins): ignoring address space is technically wrong, pointers in - // different address spaces can have different sizes - // (but TargetDataLayout doesn't currently parse that part of the DL string) - Pointer(_) => dl.pointer_size, + Pointer(a) => dl.pointer_size_in(a), } } @@ -1114,10 +1340,7 @@ impl Primitive { match self { Int(i, _) => i.align(dl), Float(f) => f.align(dl), - // FIXME(erikdesjardins): ignoring address space is technically wrong, pointers in - // different address spaces can have different alignments - // (but TargetDataLayout doesn't currently parse that part of the DL string) - Pointer(_) => dl.pointer_align, + Pointer(a) => dl.pointer_align_in(a), } } } @@ -1421,8 +1644,8 @@ impl<FieldIdx: Idx> FieldsShape<FieldIdx> { pub struct AddressSpace(pub u32); impl AddressSpace { - /// The default address space, corresponding to data space. - pub const DATA: Self = AddressSpace(0); + /// LLVM's `0` address space. + pub const ZERO: Self = AddressSpace(0); } /// The way we represent values to the backend |